Aims: To compare mosaicplasty with microfractures in the knee joint osteochondral defects treatment. Methods: Between 1998 and 2001 twenty-three patients underwent mosaicplasty and 23 patients (controls) microfracture procedures for the knee joint osteochondral or chondral pathology treatment. Patients were selected and evaluated randomly through ICRS and modiþed HSS scales, arthroscopicaly, histologically, rent-genologicaly and with MRI. Average follow-up was 12,4(range 10–14 months) and 23,6 months (range 22 –25 months). Results: The defect-size in these patients ranged between 12 mm² and 23 mm² in diameter and had an average-size of 15 mm². 22(95,6%)mosaicplasty results were excellent and good at the time of last follow-up. 16(69,5%) in the control group results were excellent and good and 7(30,4%) Ð fair 23,6 months post operations. Modiþed ICRS and HSS evaluations showed statistically signiþcantly better results in the mosaic-plasty group at the 12,4 and 23,6 months (p< 0.005; p< 0.0001) post operations. Last follow-up showed deterioration in microfracture group (p< 0,02). Conclusions: Mosaicplasty can be recommended for the treatment of osteochondral defects in the weight-bearing area of the knee as a safe procedure for transplantation of hyaline cartilage.